Association Between Mild Autonomous Cortisol Secretion and Hepatic Fat Fraction in Patients With Adrenal Adenomas: A Chemical Shift <scp>MRI</scp> Study

RATIONALE AND OBJECTIVES: This study aimed to evaluate the relationship between mild autonomous cortisol secretion (MACS) caused by adrenal adenomas and hepatic fat fraction (HFF) measured by dual-echo Dixon chemical shift-encoded MRI (dual-echo CSE-MRI). METHODS: This retrospective study included 151 patients with 169 adrenal adenomas evaluated between November 2023 and November 2025. According to post-1 mg dexamethasone suppression test (DST) cortisol levels, patients were classified as having MACS or non-functioning adrenal incidentalomas (NFAI). HFF was quantitatively assessed using dual-echo CSE-MRI. Clinical, biochemical, and imaging findings were analyzed. Correlation analyses and multivariate regression models were used to identify factors associated with hepatic fat fraction and MACS. RESULTS: Forty-five adrenal adenomas (26.6%) were classified as MACS. HFF was significantly higher in patients with MACS compared with those with NFAI (16.0% ± 13.3% vs. 7.1% ± 7.6%, p < 0.001). HFF showed a significant positive correlation with post-DST cortisol levels (r = 0.316, p < 0.001) and fasting glucose levels (r = 0.312, p < 0.001). In multivariate logistic regression analysis, hepatic fat fraction remained independently associated with MACS (OR: 1.084, p < 0.001). Multivariate linear regression analysis demonstrated that post-DST cortisol levels, fasting glucose levels, and age were independently associated with HFF. CONCLUSION: Hepatic fat fraction measured by dual-echo CSE-MRI is increased in patients with MACS and is associated with cortisol excess.